Resumo

PORRAS, Ernesto Germán; RODRIGUEZ PULECIO, Sara  e  CORONADO, John Jairo. A fracture study of a connecting rod from a refrigeration compressor. Ing. Investig. [online]. 2010, vol.30, n.1, pp.130-135. ISSN 0120-5609.

This paper analysed the fracture of a connecting rod from a food product refrigeration compressor. According to the connecting rod-crank mechanism´s operating characteristics, the element being studied was subjected to variable load cycles. Connecting rod loads are compressive in normal operating conditions; however, an increased friction coefficient induces flexion load. Based on the connecting rod´s microstructures, fracture surface characterisation and stress state estimation, it was concluded that the failure originated in a breakdown of connecting rod-crankshaft lubrication causing scuffing, severe wear and a high friction coefficient. Likewise, the results showed that when the friction coefficient increased to 0.4, then stress reached levels above those acceptable for the connecting rod material (molten aluminium-silicon alloy) being considered. Manufacture defects, pores and cracks increased stress concentration, thereby contributing to the mechanical element´s failure.

Palavras-chave : connecting rod; compressor; lubrication; wear; friction coefficient.

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